Sealing plugs for closing holes in walls comprising an elastic body and a stem, such that by pulling on the stem the elastic body expands radially, are known. Such plugs are widely used for sealing the holes present in concrete walls. As is well known, concrete walls are manufactured allowing a gap between formwork panels which are arranged facing one another. Said panels are secured to one another by means of transverse bolts having threaded ends projecting out of the panels in order to be able to screw on the corresponding nuts. Once the panels are secured, concrete is poured into the gap that is arranged between the formwork panels. To prevent the concrete from adhering to the transverse bolts once it sets, said bolts are usually first covered or placed inside a protective tube (usually made of plastic) which is sometimes removed when the formwork is stripped and other times not. Once the concrete has set, the formwork panels and transverse bolts are disassembled. So once said transverse bolts are disassembled, they generate through holes in the concrete wall that must be closed and sealed, particularly if the wall is intended for holding a fluid, such as water, for example, to prevent water seepage.
In that sense, ES1060376 U discloses a sealing plug comprising an elastic body and a stem assembled coaxially. The elastic body comprises a main cylindrical body and a through hole to allow the passage of the stem. The stem comprises a head which abuts with one end of the main body, whereas a washer having stop functions is arranged at the other end. When the stem is pulled on by the free end with the aid of a riveter or the like, the elastic body is compressed between the head of the stem and the stop washer, causing a radial expansion such that the elastic body fits over the hole of the concrete wall.